Incinerator wall and door structure

ABSTRACT

An incinerator having air-cooled walls and door construction surround a burning compartment in which circulation of combustion air and generated gases is provided at a known pressure, the door having inner and outer circumferential seals with the encircling portion of the wall, and means for circulating air through the interior of the walls and of the door at a pressure slightly higher than the pressure within the burning compartment to prevent smoke leakage around the door.

United States Patent [191 Hapgood et al.

[ Oct. 28, 1975 INCINERATOR WALL AND DOOR STRUCTURE [75] Inventors:William H. Hapgood, Concord;

Robert D. DiNozzi, Dedham, both of Mass.

[73] Assignee: Raytheon Company, Lexington,

Mass.

[22] Filed: Nov. 1, 1974 21 Appl. No.: 520,080

[52] US. Cl. 110/18 R; 110/173 R [51] Int. Cl. F23G 5/00; F23M 7/00 [58]Field of Search 110/8 R, 8 C, 18 R, 18 C, 110/173;126/190, 21 R [56]References Cited UNITED STATES PATENTS 1,873,076 8/1932 Van Ackeren110/173 X 1,880,600 10/1932 Umbel 110/173 X 2,641,209 6/1953 Lowe110/173 Knowles 110/18 2,847,951 8/1958 Triggs 110/8 3,121,158 2/1964l-lurko 126/190 3,150,619 9/1964 Brucken et al. 110/8 3,364,887 l/1968Bourner 1lO/8 Primary Examiner-Kenneth W. Sprague Attorney, Agent, orFirml-1arold A. Murphy; Joseph D. Pannone; John T. Meaney [57] ABSTRACTAn incinerator having air-cooled walls and door construction surround aburning compartment in which circulation of combustion air and generatedgases is provided at a known pressure, the door having inner and outercircumferential seals with the encircling portion of the wall, and meansfor circulating air through the interior of the walls and of the door ata pressure slightly higher than the pressure within the burningcompartment to prevent smoke leakage around the door.

8 Claims, 5 Drawing Figures US. Patent Oct.28, 1975 Sheet1of2 3,915,104

U.S. Patent Oct. 28, 1975 Sheet 2 of2 3,915,104

l00vig L/LJ INCINERATOR WALL AND DOOR STRUCTURE BACKGROUND OF THEINVENTION In the manufacture of burning appliances such as incinerators,for example, it is of primary importance that precautions be taken toprevent escape of smoke into the ambient atmosphere. This isparticularly true of incinerators which are used in confining spacessuch as household incinerators used in a kitchen or other room, or otherincinerators such as used in hospitals or small commercialestablishments.

In the interests of safety, it is also highly desirable to provide anincinerator construction wherein the outer wall surfaces, including thecharging door, are maintained at low temperature levels while theappliance is being used.

It has been common practice to provide seals around the edge of doors toprevent leakage of smoke under normal conditions of use. However, it hasbeen difficult to provide smoke-preventing seals in appliances whererelatively high temperatures are encountered during a burning cycle.High temperature materials of conventional economically purchasedmaterials usually do not provide efficient sealing capabilities, whilereadily available low temperature materials such as rubber, for example,have limited temperature capabilities.

Natural convection cooling of a door or wall is inadequate and, sincecome type of forced air cooling is re quired, the seal also should besuch as will be compatible with forced air circulation.

SUMMARY OF THE INVENTION The above and other objections to known burningappliances are overcome by the present invention wherein the interiorburning compartment is enclosed within a double-walled jacket includinga doublewalled hinged door through which access is had to thecompartment. Cool air is directed under pressure through the spacebetween the walls of the jacket and also through the space between thewalls of the door. This has been found to maintain the outer surfaces ofthe walls and door at a safely low temperature.

An outer seal between the edge of the door and its encircling frame inthe wall of the jacket is adequately and conveniently of a lowtemperature material such as rubber, and prevents the forced cooling airfrom escaping. A second inner peripheral seal is located between thedoor and frame inwardly of the first seal and comprises a hightemperature material such as fiber glass braid with a stainless steelmesh core. Such a high temperature material is somewhat porous, however,and normally smoke from the burning compartment would seep through intothe space between the door and frame since combustion air and gaseswithin the compartment are maintained at pressures higher than normalambient air pressures.

Therefore, in further accordance with this invention, means is providedfor introducing the forced cooling air into the space between the doorseals as it flows through the jacket and door walls, with such forcedair flow being at a pressure slightly greater than the pressure withinthe burning compartment. For example, with a pressure of about 0.15-0.25iwc within the compartment, and with cooling air being circulated at apressure of about 0.3 iwc, it will be apparent that a small amount ofthe circulating cooling air will percolate through the inner hightemperature seal into the burning compartment. No air will travel in thereverse direction through the inner seal and thus no smoke will escapethrough the door.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objectives andadvantages of this invention will become apparent from the followingdescription taken in connection with the accompanying drawings, whereinFIG. 1 is an isometric view of an incinerator embodying the invention;

FIG. 2 is a vertical sectional view taken substantially on line 22 ofFIG. 1 looking in the direction of the arrows;

FIG. 3 is a horizontal sectional view taken substantially on line 33looking in the direction of the arrows;

FIG. 4 is a fragmentary enlarged vertical sectional view taken throughthe incinerator door and adjacent portions of the incinerator jacket;and

FIG. 5 is an enlarged isometric view illustrating particularly the innerside of the incinerator door.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly tothe drawings wherein like characters of reference designate like partsthroughout the several views, the invention is shown as applied to ahousehold incinerator 10. However, it is to be understood that theinvention may be utilized with other types of apparatus such as ovens,furnaces, heaters, or the like in which it is desired that outersurfaces be kept at safely low temperatures and that no smoke, gases ornoxious products be allowed to escape around the edge of the door. Whilethe invention is shown as applied to a household incinerator, details ofthe construction and operation of the incinerator such as are notbelieved to constitute part of the present invention will not bediscussed herein but may be found in U.S. Pat. No. 3,776,148 issued onDec. 4, 1973 to the same inventors as the present invention.

The incinerator 10 is shown as including a burning compartment 12 whichis defined by an enclosing jacket having an inner rear wall 14, innerfront wall 16, inner side walls 18 and 20, and inner top and bottomwalls 22 and 24 respectively. Walls l424 are spaced from respectiveouter walls 2628303234-36 to form an air circulation space within thewalls completely around the appliance.

The inner structure may comprise a single burning compartment as shownor may be separated into multiple chambers such as combustion chamber,afterburner and flue, for example. While the inner walls are depicted inthe drawings as comprising a single layer, it is to be understood thatthese inner walls will usually consist of several layers including aninsulating fire resistant inner layer and an enclosing metal skin, withor without additional heat insulation. This inner structure is mountedas by a number of legs 38 so as to retain the spaced relation to theouter wall structure and thereby maintain the air circulation spacetherebetween.

A hinged door 40, to be described, is mounted at the front of theappliance to provide access means whereby a charge to be burned may beput into the burning compartment. As shown in FIG. 1, a storage area maybe provided in the form of a slidable drawer 42, and a secnd smallerdrawer 44 may be provided for ash re moval or other purposes as desired.

Upon one side wall 32 is conveniently mounted a housing 46 (FIG. 3)which encloses the drawers 42 and 44 at its forward end, and whichencloses a volute 48 having a conventional motor and fan which thusforms an air circulating blower or pump 50. An input orifice 52 isprovided in wall 32 to allow air to enter the blower 50 and a secondorifice 54 allows air to be forced by the pump into the air circulationspace 66 between the inner and outer walls of the jacket.

A gas or oil-fueled burner 56 of any conventional or known type isprovided at a suitable location to provide incineration of a charge inthe burning compartment.

The burner 56 may be ignited in any suitable manner and may becyclically or otherwise controlled such as taught, for example, inaforementioned US. Pat. No. 3,776,148.

Input of cooling air is achieved through an external vent terminal box58 which is mounted on the rear wall 26 by an outer pipe 60 whichcoaxially encircles an exhaust pipe 62, pipe 62 permitting exhaust ofair from within the space 64 between the jacket rear walls. Input ofcool air is achieved through apertures 64 in a portion of the terminalbox nearest the wall 26, which air travels into the circulation space 64between walls 14 and 26 as indicated by arrows in FIGS. 2 and 3. Thiscool air is drawn into the blower 50 through port 52 and is thenforcibly expelled through port 54 into space 66 between side walls 20and 32, from which it passes into the door area.

The door 40 comprises a closed hollow front panel 68 which includesspaced front and rear walls 70 and 72 respectively. A central rearportion 74 of the door projects rearwardly into the interior of theburning compartment and comprises a boxlike member of high temperaturematerial such as stainless steel, for example, which is filled withinsulating material 76 such as ceramic fiber, for example.

The inner and outer front walls 16 and 28 of the jacket are shaped toprovide an opening to receive the door 40 as clearly shown in FIGS. 2and 4 and the peripheral edge of this opening is sealed by an angledframe 78 within which the door 40 resides when in closed position, asillustrated. At the bottom the door is hinged in any suitable manner,such as by hinge members 80 fixed to the door at their upper ends andpivotally secured at their lower ends to a bracket 82 carried by one ofthe front walls 16 or 18.

Frame 78 includes an angled portion 84 which extends around the openingso as to overlie the inner or rear wall 72 of the door and has aninwardly directed peripheral flange 86 to define a smaller openingwithin which the projecting portion 74 of the door resides when the dooris closed.

Portion 84 of the frame is provided with a number of vertically arrangedvents or ports 88 (FIGS. 3 and on either side of the door, and the rearwall 72 of the door has similar cooperating vents or ports 90. Thus,cool air is enabled to flow from space 66, through vents 88 and 90 inthe adjacent side of the frame and door into the interior of the doorpanel 60 to cool the front of the door. From the interior of the doorpanel the air then flows out through the vents and ports in the opposite side of the door and frame into the space 92 between sidewalls 18and 30 of the jacket. From space 92, this air then passes into space 94between the rear walls 14 and 26 of the jacket and exits into exhaustpipe 62. From the end of the exhaust pipe 62 this air is directedupwardly and out through vents in the top of the terminal box 58.

Incidentally, hot air and gases from within the burning compartment alsoexits by means of a short exhaust pipe 96 directly into exhaust pipe 62.

It will be apparent that some substantial amount of the circulating coolair flowing from the jacket through the door normally would tend toescape out around the edge of the door between the door and frame. Thisis prevented in the present invention by the provision of an O-ring typeouter seal 98. Outer seal 98 is fixed the doors inner wall 72 around theperipheral edge thereof and is adapted to be compressed between the wall72 and adjacent frame 78 when the door is closed. Being located in arelatively cool region, the outer seal 98 is a low temperature materialsuch'as rubber, plastic or the like having efficient air-sealingcharacteristics.

An inner seal 100 is mounted on the door inner wall 72 encircling andadjacent the projecting portion 74 thereof. This region where the innerseal 100 is located becomes relatively hot and, therefore, rubber orother low temperature material will rapidly deteriorate when theincinerator is used. This problem is overcome by employing a hightemperature material such as fiber glass braid for the inner seal. Suchmaterial is slightly porous, but it will resist the high temperatures towhich the inner seal 100 is subjected.

In order to prevent leakage of hot air and gases out of the burningcompartment through inner seal 100 into the space around the edge of thedoor, the air circulating through the door and jacket is at a pressureslightly greater than the pressure within the burning compartment. Forexample, if the pressure within the burning compartment is about0.15-0.25 iwc, for example, the pressure of the circulating cool air mayconveniently and satisfactorily be about 0.3 iwc. In such a case, therewill be slight percolation of the cool circulating air through the innerseal 100 into the burning compartment. Such percolation is very small,depending upon the porosity of the material of the inner seal 100, andwill not adversely effect the operation of the apparatus.

Actual pressures within the burning compartment will result from theinherent combustion process which is supplied with air for combustionpurposes from the blower 50, such as via a pipe 104 leading from theblower into the burning compartment, or elsewhere, as is well known.Control of the air pressure within the walls of the jacket and door isachieved in many ways, such as by control of the size of an outletaperture 102 (FIG. 2) adjacent the exhaust pipe 62.

From the foregoing it will be apparent that all of the objectives andadvantages of this invention have been achieved by the novel apparatusshown and described. It will also be apparent, however, that variousmodifications and changes in the structures shown and described may bemade by those skilled in the art without departing from the spirit ofthe invention as expressed in the accompanying claims. Accordingly, allmatter shown and described is to be interpreted as illustrative and notin a limiting sense.

What is claimed is:

1. An appliance comprising a burning compartment surrounded by a jacket,said jacket having air circulation passages therein, a door in saidjacket communieating with the interior of the burning compartment, saiddoor having an air circulation passage therein, port means cooperativelyinterconnecting the air circulation passages in the door and jacket,means for circulating air within the interior of the burning compartmentat a known pressure, and means for circulating cooling air through saidair circulation passages in the door and jacket at a pressure slightlygreater than the pressure of the air within the burning compartment.

2. An appliance comprising a burning compartment surrounded by anenclosure, an opening in said enclosure, a frame supported in saidenclosure and outlining said opening, a door removably positioned insaid frame in closing relation to said opening, and sealing meansbetween said door and frame, said sealing means comprising a pair ofspaced resilient O-ring members, one of said sealing members beinglocated inwardly of the other and effectively nearer the burning compartment, the outer of said sealing members being substantially resistant topassage of air therethrough, and the inner sealing member being porous.

3. An appliance as set forth in claim 2 wherein the outer of saidsealing members is rubber or plastic, and the inner sealing member isfiber glass braid.

4. An appliance comprising a burning compartment surrounded by anenclosure, said enclosure comprising walls having air circulationpassages therein, an opening in said enclosure for communication withthe interior of said burning compartment, a frame supported by saidenclosure and outlining said opening, a door removably positioned inclosing relation to said opening, said door comprises a front panel anda rear panel and having an air circulation passage disposed between saidpanels, said rear panel extends across said opening, said frame has asubstantially planar portion extending around said opening in overlyingand substantially parallel relation to said rear panel, sealing meansbetween said door and said frame comprising a pair of spaced resilientO-ring members, one of said sealing members is located inwardly of theother and effectively nearer the burning compartment, the outer sealingmember is substantially resistant to passage of air therethrough, saidinner sealing member is porous, port means cooperatively interconnectingthe air circulation passages in the door and enclosure walls via thespace between said members, and means for circulating cooling airthrough said air circulation passages in the door and walls.

5. An appliance as set forth in claim 4 wherein said air circulatingmeans includes means for also directing air into the interior of theburning compartment at a known pressure, and means for directing saidcooling air through said walls and door at a pressure slightly greaterthan the pressure within the burning compartment.

6. An appliance comprising a burning compartment surrounded by anenclosure, said enclosure having spaced inner and outer walls definingan air passage therebetween, an opening in said enclosure communicatingwith the interior of the burning compartment, a door removablypositioned in closing relation to said opening, said door comprisingfront and rear panels defining an air passage therebetween, portscooperatively interconnecting the air passages in the walls and door,means for circulating air through said burning compartment at a knownpressure, and means for circulating cooling air through said wall anddoor passages via said ports at a pressure slightly greater than thepressure of the air within the burning compartment.

7. An appliance as set forth in claim 6 wherein a pair of spaced innerand outer O-ring seals are disposed between the door and surroundingwall of the enclosure, and said inner seal is porous whereby some of theair flowing from said passage in the wall toward said passage in thedoor will percolate into the burning compartment.

8. An appliance as set forth; in claim 1 wherein sealing means isprovided between said door and jacket comprising an outer substantiallynonporous member, and an inner member which is porous to the higherpressure air within the jacket and door.

1. An appliance comprising a burning compartment surrounded by a jacket,said jacket having air circulation passages therein, a door in saidjacket communicating with the interior of the burning compartment, saiddoor having an air circulation passage therein, port means cooperativelyinterconnecting the air circulation passages in the door and jacket,means for circulating air within the interior of the burning compartmentat a known pressure, and means for circulating cooling air through saidair circulation passages in the door and jacket at a pressure slightlygreater than the pressure of the air within the burning compartment. 2.An appliance comprising a burning compartment surrounded by anenclosure, an opening in said enclosure, a frame supported in saidenclosure and outlining said opening, a door removably positioned insaid frame in closing relation to said opening, and sealing meansbetween said door and frame, said sealing means comprising a pair ofspaced resilient O-ring members, one of said sealing members beinglocated inwardly of the other and effectively nearer the burningcompartment, the outer of said sealing members being substantiallyresistant to passage of air therethrough, and the inner sealing memberbeing porous.
 3. An appliance as set forth in claim 2 wherein the outerof said sealing members is rubber or plastic, and the inner sealingmember is fiber glass braid.
 4. An appliance comprising a burningcompartment surrounded by an enclosure, said enclosure comprising wallshaving air circulation passages therein, an opening in said enclosurefor communication with the interior of said burning compartment, a framesupported by said enclosure and outlining said opening, a door removablypositioned in closing relation to said opening, said door comprises afront panel and a rear panel and having an air circulation passagedisposed between said panels, said rear panel extends across saidopening, said frame has a substantially planar portion extending aroundsaid opening in overlying and substantially parallel relation to saidrear panel, sealing means between said door and said frame comprising apair of spaced resilient O-ring members, one of said sealing members islocated inwardly of the other and effectively nearer the burningcompartment, the outer sealing member is substantially resistant topassage of air therethrough, said inner sealing member is porous, portmeans cooperatively interconnecting the air circulation passages in thedoor and enclosure walls via the space between said members, and meansfor circulating cooling air through said air circulation passages in thedoor and walls.
 5. An appliance as set forth in claim 4 wherein said aircirculating means includes means for also directing air into theinterior of the burning compartment at a known pressure, and means fordirecting said cooling air through said walls and door at a pressureslightly greater than the pressure within the burning compartment.
 6. Anappliance comprising a burning compartment surrounded by an enclosure,said enclosure having spaced inner and outer walls defining an airpassage therebetween, an opening in said enclosure communicating withthe interior of the burning compartment, a door removably positioned inclosing relation to said opening, said door comprising front and rearpanels defining an air passage therebetween, ports cooperativelyinterconnecting the air passages in the walls and door, means forcirculating air through said burning compartment at a known pressure,and means for circulating cooling air through said wall and doorpassages via said ports at a pressure slightly greater than the pressureof the air within the burning compartment.
 7. An appliance as set forthin claim 6 wherein a pair of spaced inner and outer O-ring seals aredisposed between the door and surrounding wall of the enclosure, andsaid inner seal is porous whereby some of the air flowing from saidpassage in the wall toward said passage in the door will percolate intothe burning compartment.
 8. An appliance as set forth in claim 1 whereinsealing means is provided between said door and jacket comprising anouter substantially nonporous member, and an inner member which isporous to the higher pressure air within the jacket and door.